The one indoor pool tri I did had us group ourselves by speed (I went with the slow group, naturally), then they had us start in the pool at ten second intervals. In the pool we'd go up one lane, down the next, up the next, and so on until we reached the end of the pool. It was, obviously, a short swim, but it kept people moving so there wasn't ever a long wait to get started. It got chaotic in the pool, though, when people tended to glom up going under the lane ropes. I don't know how they'd do it with a longer swim portion of the race. No wetsuits in pools--I just wore tri shorts and top, then because it was a bit chilly that day I threw another shirt on over my tri top for the rest of the race. I saw other people in regular swim suits, but I don't know what they wore for the rest of the race.

Race volunteers keep the bikes safe while you're off doing other things--the transition area is closed to anyone except racers so no one is going to really be motivated to damage or steal your stuff anyway, and the volunteers patrol the area. It felt weird walking away from an unlocked bike the first time, and I imagine that at some races security is an issue, but I've never heard of a problem.

Good luck!

Sarah